I have to point out that the redguards may have elephants, but even if they did i doubt they're going to try pulling a Hannibal with a trade caravan, especially when they already have camels and horses.

The problem with Winterhold's walls isn't width or height, its that it doesn't properly surround the town. Io the west just being a pair of towers and the south it stops twice and is replaced by buildings. If someone where to attack the town they could just hop over into someones yard or smash through a window and climb in. Having the walls out a bit more with a gap between them and the buildings would make more sense from a defensive position, providing time for the defeners in the city to respond or for the mages in the towers to deal with the interloper. (And also the visual effect of approaching the town to see the broken walls and towers, the most obvious symbols of city fallen from glory.)
Sorry to put this before your other replies, only noticed once id already pressed submit.

So are you trying to say they need more walls? Falkreath got fully enclosed with walls and made two stories and dawnstar also got enclosed and remade in stone. What other changes you want that haven't been announced?

Im a bit unsure on the town wall, i get that the terrain provides most of the defenses of the city, but from the road the wall looks like just a glorified fence. Having it extended from the mountains to the sea cliff would look much more defensible and very imposing when its ruined. Otherwise the only problem i can see is that where the buildings meet the ground it looks a little to flat, maybe add some snow or raise the terrain around the base?

You need a concept, a basic outline and a team of at least four people. And before that its advised that you do some work for other projects to get a feel for how everything works. If you want to revive lost isles Roscrea, Morrowind and Atmora would be the best places to start.

Well to answer the first part, you on the forums.
To the second, yeah the x-box cant handle the load so youll have to get a PC, but rejoice that means youll also get to use SKSE and all those wonderful mods as well.

You know given how many good sepernt mods got released last year i wonder if a proper Pyandonea project is actually worth considering. Could help provide a solid base to eventually plan a Valenwood or Alianor project.

Would you consider integrating "Historic Markarth"? The mod author was unable to continue work due to health reasons so made it freeuse.
Id say its the most lorefriendly and grounded markarth overhaul, not to mention would fit alongside Holds nicely.